F15driver

My Feedback: (24)

Had my first 2 flights with the F-18 yesterday. Balanced per the CG plans just aft of the front carbon fiber wing rod with only the UAT full and other tanks empty, wheels down. On takeoff the plane leaped off the ground with half flaps after achieving takeoff speed. Controlled with down elevator and all OK until trimming. Airplane exhibited a strong tendency to climb, implying an aft CG. Also it req'd a lot of right aeliron trim which, after the first landing, I trimmed the right horozional stab a little down at the front. The second flight was a little better as far as needing right trim but it still wanted a lot of down trim. I did build this one without wheel doors and there was a lot of drag from the lack of doors. Heres the questions: 1) Has anyone used the CG per the plans sheet and found it correct, and 2) has anyone built this plane without doors and found their absence a major issue as far as trim is concerned? I'm using a TJT turbine rated at about 27 lbs. and I needed all of it to fly this airplane. Haven't weighed it yet but its pretty clear I'm well below 1:1 thrust to weight. All comments appreciated as I would like to improve the handling on the next flights.
Rob

squirt!

Rob,

I have the SM F-18...think it might be the same plane depending on who you ask...I dont have doors on mine. I think there is some significant drag by doing so. I just cant bring myself to install 9 doors and all the headaches that go with gear doors. I just like the simplicity of no doors. I have a P120 in mine so I think I have even less thrust than you and I'm at full power for most of the flight. I would put something bigger in it, but I just dont think the fuel capacity would support it.

As far as the CG goes...I think on mine I started where SM had the CG and slowly moved it back as it was considerably nose heavy. However, Im sure JL has put out a new set of instructions. The plane looks outstanding in the air...but it is a handful to fly.

Good luck!

JoelP

My Feedback: (20)

I just finished a Tam's Supa Hornet with the 9 gear doors. I think you'll find that they're time consuming to install but not at all difficult to do. I can't speak about the other F-18's out there, but the doors on this one fit really well and the plumbing was straight forward. I put air to the system the other night and the gear/doors worked perfect...freakin awesome watching those doors close!
I saw the second flight on Rob's F-18 and I think there is a lot of drag with the doors off. I agree that the plane looks good in the air and looks awesome on final when the nose assumes high AOA for landing! Good job on the build Rob and congrats again!!!

meps

My Feedback: (10)

I've always balanced my airplanes in the flight configuration.(wheels up) I think one of the problems you're having is that you balanced yours with the wheels down. After take off, you retracted your gear and some weight was shifted aft as the F-18 mains retract to the rear. I think if you balance your plane with the gear retracted, it will get you closer to the desired flight characteristics you'd like.

ravill

My Feedback: (11)

Rob,

The F-18c is my favorite airplane and I fly the living crappola outta mine. She is a sweet heart to me. I have flown a total of 3 different F-18c's (2 SM, 1 JL) and I've got another one from xtreme jets on it way. That is how much I love this airplane. She is an honest airplane and the closest scale airplane that flies like a sport plane.

1. I have learned that on Hornets, resist the urge to move the cg back. The leading edge extensions can make for some really bad tendancies on final and on your flare. This is especially true on superhornets. I know this by personal experience. Do a search.

I have the cg right on the front carbon spar, wheels down, fuel in the UAT, and love it.

2. I HATE GEAR DOORS. I use them ONLY if the plane has already got them or the manufacture tells me exactly where to put them.

I've attached vids of the first day of flying the JL F-18C. I cannot speak enough about how much I love this airplane. Oh, and I use tailerons on mine.

http://video.google.com/videoplay?do...06470651&hl=en

http://video.google.com/videoplay?do...71566069&hl=en

Once you figure out these problems, you're gonna love her, I promise. I'm thinking that your CG is a little aft.

Raf

Mach1

My Feedback: (5)

Raf,

What size engine(s) are you using in your F18's.

ravill

My Feedback: (11)

I flew two with p-120's and my JL has a Titan. They fly fine with 120's and have great vert with titans!

Raf

F15driver

My Feedback: (24)

Raf,
Ditto the above question re engine size. It seems you have gobs of vertical. How did you immobilize the ailerons as you're using tailerons? I'm going to use the earlier suggestion of balancing with wheels up and see if it moves the CG to the front carbon fiber wing rod.
Thanks all for suggestions.
Rob

ravill

My Feedback: (11)

I didn't immobalize the ailerons! I use tailerons and ailerons.

After many flights I have seen that the best, scale, take offs, for me, are achieved as follows.

Full throttle roll out and with some ground speed just start to pull on the elevator until the nose just rotates and keep the elevator at a postion that keeps the nose at the angle that I want. And I am using full flaps (~35 degrees).

I found that this works better than holding full elevator for the lift off.

Like I said, moving the CG back will make the plane roll a little better, fly inverted a little better, but can turn the airplane into a bear to land! I moved the Cg back from the former to the carbon spar (1cm or so) and that is all I am willing to go, esp after my lessons with my superhornet.

Raf

ravill

My Feedback: (11)

Oh and don't be scared to deploy the airbrake to land. That lets you carry a little more power to the runway.

I deadsticked my JL f-18c at BTW a few weeks ago (stripped engine mount causing the engine too move and pinch the fuel line[sm=what_smile.gif] ) and was surprised at how much it glid! I wouldn't suggest that you try that, however.

Raf

erbroens

Ditto on Raf´s comments on the takeoff technique. The F-18 rotation is super smooth if done this way.



Enrique

JohnMac

Hi Ravill,
So whats the story with the Superhornet? I have a SM version half built and I have heard that they are more tricky to land than the C version. Is that so?
Regards,

John

NUNU

hell no....the super is designed ...if you believe in scale...to fly better than the C don't get mad at me people ask the manufactuer...anyway on the super use the flaps and it wont be a problem...and yeah cg at 125mm ffrom leading edge......the super was and is my first jet.

F15driver

My Feedback: (24)

Raf,
Tell me more about coupling the horizontal stab to the aileron. I understand thats how the full-size F-18 is configured.
How did you couple the two and approximately how much throw did you employ on each at full deflection? It makes sense to do this but, as you know, no instruction comes with the kit as far as throw amounts are concerned.
I moved the CG to almost right onto the wing carbon fiber rod. This took an addt'l 3 oz. of lead, making 9 oz. in total with both batteries in the nose.
Will take you up on your suggestion of using the airbrake after I uncouple it from the brakes.
Thanks again your suggestions.
Rob

ravill

My Feedback: (11)

Nunu says that he has had much success with his super hornet and implies that it is a reasonable first jet. Congratulations to you Nunu.

I have flown and owned 2 different super hornets, Tam's f-18F and SM F-18E. I have much respect for this airplane. FACT: They fly great and have a great presence in the sky. FACT: Less wing loading on the super hornet. FACT: Large leading edge extensions, i.e. LEX.

I have had the best landings of my life with my super hornet and I've had the most surprising ballooning on flare with the super hornet causing minor damage, minor but enough to end my flying for the day. There is a few knots difference between beautiful touch down and the ugliest balooning on final. If you fly enough you will see this. The folks that I've spoken to and myself believe this is because of the large LEX on the super hornet. The SR-71 is also notorious for this tendancy.

This, by no means, should imply that you shouldn't fly one, quite the opposite! I learned tons from my super hornet and I wouldn't trade that. Landing my super hornet took alot of my concentration to get right. I just want to fly and have fun. I have to concentrate hard enough at work.

I've decided that I don't want a super hornet right now. That's just me. I respect the super hornet. There is a reason why you don't see them being flown all over the place. And those who do, respect them.

Fly the crap outta your SUPA and have a blast. That's what I say.

Raf

ravill

My Feedback: (11)

Rob,

I put the ailerons on a Y and just used a free channel to mix to the aileron stick on my 10x. I used eyeball throws on the ailerons and the tailerons. If I had to guess, 3/4 inch on the ailerons, and 1 to 1 1/2 inch on the tailerons It may be a bad habit of mine, but I always give my self the absolute most elevator I can on high throws on all of my airplanes. I believe there is no such thing as being able to get too much elevator!

I also have some lead in the nose as well as both my batteries. Believe me, the C is quite an enjoyable scale jet. Like I said before it has been the closest to a sport plane, SCALE jet I've ever flown and absolutely love them. You will enjoy this one as well.

Raf

JohnMac

Hi Raf,
That is first class information there. For some reason there seems to relatively few F-18's flying in the UK, certainly none local to me. This is despite at least 6 being bought by club members. They have all been sold or remain unbuilt except the C which I am about to buy. This was built by a guy who was quite out of his depth with this plane, hence he is selling it. But the best pilot in the club has flown it for him several times, and reckoned it was a bear. I flew it once, lost the canopy on take off and expected the worst, but it was a non event. It even landed like it was on rails.
Never seen an E of an F fly, which is why your insight here is so valuable. I will remember to be careful with the flare. Question! do the airbrakes help control this tendency at all being on top of the LEX's?
Regards,

John

ravill

My Feedback: (11)

John,

Sorry, I missed your question. The only superhornet, to my knowledge, that comes with airbrakes are the SM and Feibao ones. The non superhornets (the C's) absolutely love the airbrakes. No pitching tendancies what so ever when deployed and help slow her down for flare.

The E model from SM that I flew seemed to fly just fine with the airbrakes deployed. I only landed the E model twice and it ballooned on my once. On my F I didn't have any airbrakes but she ballooned on my a few times, especially when I moved the CG back.

In short, I don't know if the airbrakes would help ameliorate that ballooning tendancy.

Raf

morro

Hi all, I have just bought the JL F18 kit, and I was wondering if I could get some help as to how I can do the rivet detail, I have tried the old method of glue and I have also tried the soldering iron but I am sure there are some people out there that have a better idea.

The hoenet is going to be fully detailed with opening canopy, cockpit etc etc so if I can get some help on the riveting it would be much appreciated.

cheers
Todd

ravill

My Feedback: (11)

You should probably try the building threads. You could also call Tam as his builder puts rivets on his hornet.

Raf

cmjets

Hello:

I need know the exact point for the CG of Jet Legend F-18, If I put it in the plans situation (30mm back front aluminium spar) I need a lot of ballast in the nose. I have canopy operative and three batteries in the practicable nose, but I look the CG and the back go down too much.

HELP, please.

Many thanks in advance.

Carlos Márquez.
____________________________
http://cmjets.blogspot.com/

erbroens

Hi Carlos, I presume this is almost the same airplane from SM. Here we had to put almost 500 grams of lead at the nose for proper balancing.

don´t try to fly a tail heavy bug!


Enrique

cmjets

Hola Enrique:

500gr of lead.......... WOW.[X(][X(][X(]

Really I think that I need a lot of, but I don´t know how mcuh. Tomorrow I will know.

Many thanks my Friend.

Carlos Márquez.
________________________________
http://cmjets.blogspot.com/

FalconWings

My Feedback: (57)

drooooooling!

cmjets

FalconWings:

What ???

I think that is a english joke, but I not understand you, sorry, explain it, please.

Regards.

Carlos Márquez.
__________________________________
http://cmjets.blogspot.com/